1. Field of the Invention
The present invention relates to a wireless lighting control system for controlling the amount of power delivered to an electrical load from a source of alternating-current (AC) power, and more particularly, to a method of programming a lighting preset from a radio-frequency (RF) remote control.
2. Description of the Related Art
Control systems for controlling electrical loads, such as lights, motorized window treatments, and fans, are known. Such control systems often use radio-frequency (RF) transmission to provide wireless communication between the control devices of the system. One example of an RF lighting control system is disclosed in commonly-assigned U.S. Pat. No. 5,905,442, issued on May 18, 1999, entitled METHOD AND APPARATUS FOR CONTROLLING AND DETERMINING THE STATUS OF ELECTRICAL DEVICES FROM REMOTE LOCATIONS, the entire disclosure of which is hereby incorporated by reference.
The RF lighting control system of the '442 patent includes wall-mounted load control devices, table-top and wall-mounted master controls, and signal repeaters. The control devices of the RF lighting control system include RF antennas adapted to transmit and receive the RF signals that provide for communication between the control devices of the lighting control system. All of the control devices transmit and receive the RF signals on the same frequency. Each of the load control devices includes a user interface and an integral dimmer circuit for controlling the intensity of an attached lighting load. The user interface has a pushbutton actuator for providing on/off control of the attached lighting load and a raise/lower actuator for adjusting the intensity of the attached lighting load. The load control devices may be programmed with a preset lighting intensity that may be recalled later in response to an actuation of a button of the user interface or a received RF signal.
The table-top and wall-mounted master controls each have a plurality of buttons and are operable to transmit RF signals to the load control devices to control the intensities of the lighting loads. The signal repeaters initiate configuration procedures for the RF lighting control system and help to ensure error-free communication by repeating the RF signals to ensure that every device of the system reliably receives the RF signals. To prevent interference with other nearby RF lighting control systems located in close proximity, the RF lighting control system of the '442 patent preferably uses a house code (i.e., a house address), which each of the control devices stores in memory. Each of the control devices of the lighting control system is also assigned a unique device address (typically one byte in length) for use during normal system operation to avoid collisions between transmitted RF communication signals.
It is desirable to set the value of the preset lighting intensity of one of the load control devices from a remote control (e.g., from the table-top master control). Prior art wireless lighting control systems have included methods of programming the preset intensity of a load control device from an infrared (IR) remote control. To program a new lighting preset, a user adjusts the intensity of the lighting load to a desired level and then presses and holds a button on the IR remote control for a predetermined amount of time. The IR remote transmits a plurality of IR signals to the load control device while the button is held. The load control device determines that the button of the IR remote control is being held and stores the preset intensity of the lighting load as the new preset intensity. Preferably, the load control device receives a predetermined number of IR signals, e.g., ten IR signals, before determining that the button is being held. FCC limitations on average intentional power transmitted.
The Federal Communications Commission (FCC) regulates telecommunications and the use of the radio spectrum, including radio-frequency communications, in the United States. The rules of the FCC are provided in Title 47 of the Code of Federal Regulations. Specifically, Part 15 is directed towards radio-frequency devices. For control systems, such as RF lighting control systems, continuous transmissions are not allowed. However, periodic transmissions are acceptable as long as the FCC limitations on the average intentional power transmitted are observed. As a consequence of complying with the FCC regulations, RF lighting control systems can only transmit a limited number of RF signals in a given time period.
Because of the limitations on how often a control device of an RF lighting control system can transmit RF signals, an RF control device receiving an RF signal must respond rather quickly to the received RF signal, for example, after receiving only one or two RF signals. Therefore, when a button is held on an RF remote control, an RF load control device receiving an RF signal from the remote control cannot wait for ten RF signals (i.e., to determine that the button is being held) before responding to the RF signal. When a button is pressed and held on an RF remote control to program a new preset intensity, the load control device must control the lighting load immediately in response to the RF signal. Then the load control device can subsequently determine that the button is being held and store a new preset intensity. This sequence of events can be confusing to a user.
Therefore, there is a need for an improved method of programming a lighting preset of a load control device from an RF remote control.